MARCELINUS, PRIEST. — He wrote together with Faustinus the so-called *Libellus precum*. The original title is *De confessione verae fidei*, addressed (383-84) to the emperors Valentinian II, Theodosius, and Arcadius, to protest against the measures that had been taken against the followers of Lucifer of Cagliari.
This writing is the principal source for the history of the case. The publication was successful. In a rescript of the year 384, Theodosius declared himself opposed to the measures against the companions of Gregory of Elvira and Heraclides of Ossinica (PL 13, 107 sg.).
Nothing precise is known about the contribution of M. to the drafting of this writing. Isidore of Seville (De vir. ill., 14) mentions only M. as its author, but Faustinus is also known from other writings: *Adversus arianos et Macedonianos* (Gennadius, De vir. ill., 16), identical with *De fide adversus arianos* (PL 13, 37-80), and from the *Fides Theodosio imperatori oblata* (ibid., 79-80). Thus the part of M. in the compilation of the *Liber precum*, which moreover owes much to Gregory of Elvira, remains doubtful.